Otro
Nature of potential barrier in (Ca-1/4,Cu-3/4)TiO3 polycrystalline perovskite
Registro en:
Solid State Communications. Oxford: Pergamon-Elsevier B.V., v. 138, n. 1, p. 1-4, 2006.
0038-1098
10.1016/j.ssc.2006.02.001
WOS:000236570300001
Autor
Marques, VPB
Bueno, Paulo Roberto
Simoes, A. Z.
Cilense, M.
Varela, José Arana
Longo, Elson
Leite, E. R.
Resumen
The nonohmic electrical features of (Ca-1/4,Cu-3/4)TiO3 perovskite ceramics, which have very strong gigantic dielectric is believed originate from potential barriers at the grain boundaries. In the present study, we used the admittance and impedance spectroscopy technique to investigate (Ca-1/4,Cu-3/4)TiO3 perovskite ceramics with low nonohmic electrical properties. The study was conducted under two different conditions: on as-sintered ceramics and on ceramics thermally treated in an oxygen-rich atmosphere. The results confirm that thermal treatment in oxygen-rich atmospheres influence the nonohmic properties. Annealing at oxygen-rich atmospheres improve the nonohmic behavior and annealing at oxygen-poor atmospheres decrease the nonohmic properties, a behavior already reported for common metal oxide nonohmic devices and here firstly evidenced for the (Ca-1/4,Cu-3/4)TiO3 perovskite related materials. The results show that oxygen also influences the capacitance values at low frequencies, a behavior that is indicative of the Schottky-type nature of the potential barrier. (c) 2006 Elsevier Ltd. All rights reserved.